Universal Serial Bus (USB) is a widely used serial bus standard used to interface devices. USB was originally designed for computers as a plug-and-play interface between a computer and add-on devices such as, for example, audio players, joysticks, keyboards, digital cameras, scanners and printers, etc. However, the popularity of USB has prompted it to also become commonplace on other devices such as, for example, video game consoles, portable digital assistants (PDAs), portable digital video disk (DVD) and media players, cell phones, televisions (TVs), home stereo equipment such as MP3 players and iPods, car stereos, and portable memory devices. USB can be used to connect peripherals such as mouse devices, keyboards, gamepads, joysticks, scanners, digital cameras, printers, external storage, networking components, and many other devices.
As discussed above, USB is a serial bus standard to interface devices. USB is designed to allow many peripherals to be connected using a single standardized interface socket and to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer. USB also provides power to low consumption devices eliminating the need for an external power supply. Common class drivers included with the operating system generally remove the need to install device drivers.
The USB 1.0 specification was introduced in November 1995. Starting in 1996, a few computer manufacturers started including USB support in their new machines, and it became widespread in 1998 when it was used as the primary connector on the original Apple iMac introduced in May 1998. The USB connector was used to replace many PS2, serial and parallel ports. USB 1.1 was introduced in September 1998 and is an external bus standard that supports data transfer rates of 12 Mbps (Megabits per second). USB 2.0, also known as High-speed USB, is an external bus that supports data rates up to 480 Mbps. USB 2.0 is fully compatible with USB 1.1, and uses the same cables and connectors. The USB 2.0 specification was released in April 2000.
A SuperSpeed USB rate of approximately 5 Gbps (Gigabits per second) is contemplated with the upcoming USB 3.0 specification. Therefore, USB 3.0 should allow for bus speeds ten times faster than USB 2.0. In addition to these faster speeds, the present inventors have been contemplating even faster bus speeds.